Metal-dielectric bonding method and structure

ABSTRACT

A metal-dielectric bonding method includes providing a first semiconductor structure including a first semiconductor layer, a first dielectric layer on the first semiconductor layer, and a first metal layer on the first dielectric layer, where the first metal layer has a metal bonding surface facing away from the first semiconductor layer; planarizing the metal bonding surface; applying a plasma treatment on the metal bonding surface; providing a second semiconductor structure including a second semiconductor layer, and a second dielectric layer on the second semiconductor layer, where the second dielectric layer has a dielectric bonding surface facing away from the second semiconductor layer; planarizing the dielectric bonding surface; applying a plasma treatment on the dielectric bonding surface; and bonding the first semiconductor structure with the second semiconductor structure by bonding the metal bonding surface with the dielectric bonding surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Application No.PCT/CN2020/070595, filed on Jan. 7, 2020, the entire content of which isincorporated herein by reference.

FIELD OF THE TECHNOLOGY

This application relates to the field of bonding technologies and,specifically, to a metal-dielectric bonding method and structure.

BACKGROUND OF THE DISCLOSURE

Dielectric bonding is often used for bonding a carrier wafer with adevice or bonding a device with another device. The devices for bondingmay include through-silicon vias. In dielectric bonding, a dielectricsurface is bonded with another dielectric surface. Hybrid bonding oftenincludes bonding of a hybrid surface that includes a dielectric portionand a metal portion, between devices. For bonding metal surfaces,thermal compression is often used to form metal-metal bonding.

As two semiconductor structures are bonded together for 3-dimensionalintegration, more complications are introduced. Factors such as heat oran electromagnetic radiation generated by one semiconductor structuremay affect operations of one or more semiconductor structures in thebonded structures. For example, heat generated by one semiconductorstructure may not only affect its own operations, but also affectoperations of the other semiconductor structure.

The disclosed methods and systems are directed to solve one or moreproblems set forth above and other problems.

SUMMARY

One aspect of the present disclosure includes a metal-dielectric bondingmethod. The metal-dielectric bonding method includes providing a firstsemiconductor structure including a first semiconductor layer, a firstdielectric layer on the first semiconductor layer, and a first metallayer on the first dielectric layer, where the first metal layer has ametal bonding surface facing away from the first semiconductor layer;planarizing the metal bonding surface; applying a plasma treatment onthe metal bonding surface; providing a second semiconductor structureincluding a second semiconductor layer, and a second dielectric layer onthe second semiconductor layer, where the second dielectric layer has adielectric bonding surface facing away from the second semiconductorlayer; planarizing the dielectric bonding surface; applying a plasmatreatment on the dielectric bonding surface; and bonding the firstsemiconductor structure with the second semiconductor structure bybonding the metal bonding surface with the dielectric bonding surface.

Other aspects of the present disclosure can be understood by thoseskilled in the art in light of the description, the claims, and thedrawings of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a flowchart of an exemplary metal-dielectric bondingmethod consistent with various disclosed embodiments of the presentdisclosure.

FIG. 2 illustrates a schematic view of an exemplary first semiconductorlayer consistent with various disclosed embodiments of the presentdisclosure.

FIG. 3 illustrates another schematic view of an exemplary firstsemiconductor layer consistent with various disclosed embodiments of thepresent disclosure.

FIG. 4 illustrates a schematic view of an exemplary first dielectriclayer on an exemplary first semiconductor layer consistent with variousdisclosed embodiments of the present disclosure.

FIG. 5 illustrates a schematic view of an exemplary first semiconductorstructure consistent with various disclosed embodiments of the presentdisclosure.

FIG. 6 illustrates another schematic view of an exemplary firstsemiconductor structure after planarization consistent with variousdisclosed embodiments of the present disclosure.

FIG. 7 illustrates another schematic view of an exemplary firstsemiconductor structure under surface treatments consistent with variousdisclosed embodiments of the present disclosure.

FIG. 8 illustrates a schematic view of an exemplary second semiconductorlayer consistent with various disclosed embodiments of the presentdisclosure.

FIG. 9 illustrates another schematic view of an exemplary secondsemiconductor layer consistent with various disclosed embodiments of thepresent disclosure.

FIG. 10 illustrates a schematic view of an exemplary secondsemiconductor structure consistent with various disclosed embodiments ofthe present disclosure.

FIG. 11 illustrates a schematic view of an exemplary secondsemiconductor structure after planarization consistent with variousdisclosed embodiments of the present disclosure.

FIG. 12 illustrates a schematic view of an exemplary secondsemiconductor structure under surface treatments consistent with variousdisclosed embodiments of the present disclosure.

FIG. 13 illustrates a schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure.

FIG. 14 illustrates another schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure.

FIG. 15 illustrates a transmission electron microscopy image of anexemplary structure of metal-dielectric bonding consistent with variousdisclosed embodiments of the present disclosure.

FIG. 16 illustrates another schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure.

FIG. 17 illustrates another schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure.

DESCRIPTION OF EMBODIMENTS

The following describes the technical solutions in the embodiments ofthe present invention with reference to the accompanying drawings.Wherever possible, the same reference numbers will be used throughoutthe drawings to refer to the same or like parts. Apparently, thedescribed embodiments are merely some but not all the embodiments of thepresent invention. Other embodiments obtained by a person skilled in theart based on the embodiments of the present invention without creativeefforts shall fall within the protection scope of the presentdisclosure.

In the specification, claims, and accompanying drawings of the presentdisclosure, the terms “first,” “second,” “third,” “fourth,” and the like(if exist) are intended to distinguish between similar objects but donot necessarily indicate an order or sequence. It should be understoodthat the embodiments of the present disclosure described herein can beimplemented, for example, in orders other than the order it lustrated ordescribed herein.

Some or all of the processes may be chosen according to actual needs toachieve purposes of the present disclosure. Some or all of thecomponents may be chosen according to actual needs to achieve purposesof the present disclosure.

The present disclosure provides a metal-dielectric bonding method. FIG.1 illustrates a flowchart of an exemplary metal-dielectric bondingmethod consistent with various disclosed embodiments of the presentdisclosure. FIGS. 2-14 and 16-17 illustrate schematic views ofstructures at certain stages of the metal-dielectric bonding process.

Referring to FIG. 1, a first semiconductor structure including a firstsemiconductor layer, a first dielectric layer, and a first metal layerhaving a metal bonding surface is provided (S610). FIGS. 2-5 showstructures at certain stages of the process for providing the firstsemiconductor structure that includes a first semiconductor layer, afirst dielectric layer, and a first metal layer.

FIG. 2 illustrates a schematic view of an exemplary first semiconductorlayer consistent with various disclosed embodiments of the presentdisclosure. Referring to FIG. 2, a first semiconductor layer 11 isprovided. In some embodiments, the first semiconductor layer 11 may be asilicon substrate.

FIG. 3 illustrates another schematic view of an exemplary firstsemiconductor layer consistent with various disclosed embodiments of thepresent disclosure. Referring to FIG. 3, the first semiconductor layer11 may include a first semiconductor device 111 formed therein.

In some embodiments, the first semiconductor device 111 may be, forexample, a power device. The power device may generate heat.

In other embodiments, the first semiconductor device 111 may be, forexample, a complementary metal-oxide-semiconductor (CMOS) device. TheCMOS device may be used in various applications such as a CMOS imagesensor (CIS), a data convertor, etc.

In some embodiments, the first semiconductor device 111 may be, forexample, a device that generates an electromagnetic radiation. Theelectromagnetic radiation may be, for example, visible light, infraredlight, radio wave, ultraviolet, or any combination thereof.

In some embodiments, the first semiconductor device 111 may be, forexample, a device that is exposed to an electromagnetic radiation. Theelectromagnetic radiation may be, for example, visible light, infraredlight, radio wave, ultraviolet, or any combination thereof.

FIG. 4 illustrates a schematic view of an exemplary first dielectriclayer on an exemplary first semiconductor layer consistent with variousdisclosed embodiments of the present disclosure. Referring to FIG. 4, afirst dielectric layer 12 is formed on a first semiconductor layer 11.

In some embodiments, a material of the first dielectric layer 12 mayinclude, for example, silicon oxide, silicon oxycarbide, siliconnitride, silicon carbon nitride, or any combination thereof.

In some embodiments, the first dielectric layer 12 may be formed on thefirst semiconductor layer 11 by deposition, such as chemical vapordeposition (CVD), physical vapor deposition (PVD), atomic layerdeposition (ALD), or any other suitable deposition process.

FIG. 5 illustrates a schematic view of an exemplary first semiconductorstructure consistent with various disclosed embodiments of the presentdisclosure. Referring to FIG. 5, the first semiconductor structure 100includes the first semiconductor layer 11, the first dielectric layer12, and a first metal layer 13. The first metal layer 13 is formed onthe first dielectric layer 12. The first metal layer 13 includes a metalbonding surface 131, and the metal bonding surface 131 faces away fromthe first semiconductor layer 11. The metal bonding surface 131 may be asurface that is to be bonded with a bonding surface of anothersemiconductor structure.

In some embodiments, a material of the first metal layer 13 may betantalum, titanium, copper, or any combination thereof. In someembodiments, the first metal layer 13 may be formed on the firstdielectric layer 12 by deposition, such as chemical vapor deposition(CVD), physical vapor deposition (PVD), atomic layer deposition (ALD),or any other suitable deposition. For example, as a physical vapordeposition, magnetron sputtering deposition may be used to deposit thefirst metal layer 13, where one or more sputtering targets may bebombarded to eject materials, and the ejected materials may be depositedon the first dielectric layer 12.

Referring to FIG. 1, the metal bonding surface is planarized (S620).Correspondingly, FIG. 6 illustrates another schematic view of anexemplary first semiconductor structure after planarization consistentwith various disclosed embodiments of the present disclosure.

Referring to FIG. 6, the metal bonding surface 131 is flat after themetal bonding surface 131 is planarized, as the planarization processremoves materials causing rough topography. In some embodiments, themetal bonding surface 131 may be planarized by chemical mechanicalplanarization or any other suitable planarization. In some embodiments,the metal bonding surface 131 may be planarized, such that a surfaceroughness of the metal bonding surface 131 may be, for example,approximately 0.5 nm or less.

Referring to FIG. 1, surface treatments are applied on the metal bondingsurface (S630). Correspondingly, FIG. 7 illustrates another schematicview of an exemplary first semiconductor structure under surfacetreatments consistent with various disclosed embodiments of the presentdisclosure.

Referring to FIG. 7, closed sharp arrows indicate that surfacetreatments are applied on the metal bonding surface 131 of the firstmetal layer 13 in the first semiconductor structure 100. The surfacetreatments may include a plasma treatment and a cleaning treatment.

In some embodiments, the plasma treatment may include applying on themetal bonding surface 131 nitrogen plasma, oxygen plasma, argon plasma,argon-hydrogen plasma, or any other suitable plasma. Nitrogen plasma maybe generated by introducing nitrogen gas to a plasma system; oxygenplasma may be generated by introducing oxygen gas to a plasma system;and argon plasma may be generated by introducing argon gas into a plasmasystem. Argon-hydrogen plasma may be generated by introducing argon andhydrogen gases into a plasma system. Argon-hydrogen plasma may includemixture of argon plasma and hydrogen plasma.

In some embodiments, the cleaning treatment may include using deionizedwater to clean the metal bonding surface 131.

In some embodiments, the cleaning treatment may include using ahydrophilic chemical substance to clean the metal bonding surface 131.The hydrophilic chemical substance may be, for example, ammoniasolution, weak acid, or any other suitable chemical substance. The weakacid may be, for example, hydrofluoric acid, benzoic acid, acetic acid,propanoic acid, acrylic acid, or any other suitable weak acid.

Referring to FIG. 1, a second semiconductor structure including a secondsemiconductor layer and a second dielectric layer having a dielectricbonding surface is provided (S640). FIGS. 8-10 show structures atcertain stages of the process for providing the second semiconductorstructure that includes a second semiconductor layer and a seconddielectric layer.

FIG. 8 illustrates a schematic view of an exemplary second semiconductorlayer consistent with various disclosed embodiments of the presentdisclosure. Referring to FIG. 8, a second semiconductor layer 21 isprovided. In some embodiments, the second semiconductor layer 21 may bea silicon substrate.

FIG. 9 illustrates another schematic view of an exemplary secondsemiconductor layer consistent with various disclosed embodiments of thepresent disclosure. Referring to FIG. 9, the second semiconductor layer21 may include a second semiconductor device 211.

In some embodiments, the second semiconductor device 211 may be, forexample, a power device. The power device may generate heat.

In some embodiments, the second semiconductor device 211 may be, forexample, a complementary metal-oxide-semiconductor (CMOS) device. TheCMOS device may be used in various applications such as a CMOS imagesensor, a data convertor, etc.

In some embodiments, the second semiconductor device 211 may be, forexample, a device that generates an electromagnetic radiation. Theelectromagnetic radiation may be, for example, visible light, infraredlight, radio wave, ultraviolet, or any combination thereof.

In some embodiments, the second semiconductor device 211 may be, forexample, a device that is exposed to an electromagnetic radiation. Theelectromagnetic radiation may be, for example, visible light, infraredlight, radio wave, ultraviolet, or any combination thereof.

FIG. 10 illustrates a schematic view of an exemplary secondsemiconductor structure consistent with various disclosed embodiments ofthe present disclosure. Referring to FIG. 10, the second semiconductorstructure 200 includes a second semiconductor layer 21 and a seconddielectric layer 22, and the second dielectric layer 22 is formed on thesecond semiconductor layer 21.

The second dielectric layer 22 includes a dielectric bonding surface221, and the dielectric bonding surface 221 faces away from the secondsemiconductor layer 21. The dielectric bonding surface 221 may be asurface that is to be bonded with a bonding surface of the firstsemiconductor structure.

In some embodiments, a material of the second dielectric layer 22 mayinclude, for example, silicon oxide, silicon oxycarbide, siliconnitride, silicon carbon nitride, or any combination thereof.

In some embodiments, the second dielectric layer 22 may be formed on thesecond semiconductor layer 21 by deposition, such as chemical vapordeposition (CVD), physical vapor deposition (PVD), atomic layerdeposition (ALD), or any other suitable deposition.

Referring to FIG. 1, the dielectric bonding surface is planarized(S650). Correspondingly, FIG. 11 illustrates a schematic view of anexemplary second semiconductor structure after planarization consistentwith various disclosed embodiments of the present disclosure.

Referring to FIG. 11, the dielectric bonding surface 221 is flat afterthe dielectric bonding surface 221 is planarized, as the planarizationprocess removes materials causing rough topography. In some embodiments,the dielectric bonding surface 221 may be planarized by chemicalmechanical planarization or any other suitable planarization. In someembodiments, the dielectric bonding surface 221 may be planarized, suchthat a surface roughness of the dielectric bonding surface 221 may be,for example, approximately 0.5 nm or less.

Referring to FIG. 1, surface treatments are applied on the dielectricbonding surface (S660). Correspondingly, FIG. 12 illustrates a schematicview of an exemplary second semiconductor structure under surfacetreatments consistent with various disclosed embodiments of the presentdisclosure.

Referring to FIG. 12, closed sharp arrows indicate that surfacetreatments are applied on the dielectric bonding surface 221 of thesecond dielectric layer 22 of the second semiconductor structure 200.The surface treatments may include a plasma treatment and a cleaningtreatment.

In some embodiments, the plasma treatment may include applying on thedielectric bonding surface 221 nitrogen plasma, oxygen plasma, argonplasma, argon-hydrogen plasma, or any other suitable plasma. Nitrogenplasma may be generated by introducing nitrogen gas to a plasma system;oxygen plasma may be generated by introducing oxygen gas to a plasmasystem; and argon plasma may be generated by introducing argon gas intoa plasma system. Argon-hydrogen plasma may be generated by introducingargon and hydrogen gases into a plasma system. Argon-hydrogen plasma mayinclude mixture of argon plasma and hydrogen plasma.

In some embodiments, the cleaning treatment may include using deionizedwater to clean the dielectric bonding surface 221.

In some embodiments, the cleaning treatment may include using ahydrophilic chemical substance to clean the dielectric bonding surface221. The hydrophilic chemical substance may be, for example, ammoniasolution, weak acid, or any other suitable chemical substance. The weakacid may be, for example, hydrofluoric acid, benzoic acid, acetic acid,propanoic acid, acrylic acid, or any other suitable weak acid.

Referring to FIG. 1, the first semiconductor structure is bonded withthe second semiconductor structure (S670). Correspondingly, FIGS. 13-14and 16-17 illustrate schematic views of structures of metal-dielectricbonding.

FIG. 13 illustrates a schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure. Referring to FIG. 13, the first semiconductorstructure is bonded with the second semiconductor structure by bondingthe metal bonding surface with the dielectric bonding surface. In someembodiments, referring to FIG. 13, the second semiconductor structuremay be oriented upside down, such that the dielectric bonding surface isoriented downward. Further, the metal bonding surface is orientedupward. Accordingly, the dielectric bonding surface and the metalbonding surface face toward each other and bonded together.

A bonding interface 31 is form between the first semiconductor structure100 and the second semiconductor structure 200. The bonding interface 31is at a plane at which the metal bonding surface is in contact with thedielectric bonding surface.

In some embodiments, the first semiconductor structure may be bondedwith the second semiconductor structure by bonding the metal bondingsurface with the dielectric bonding surface at room temperature. Roomtemperature may be, for example, in a range from approximately 15° C. toapproximately 30° C.

In some embodiments, the first semiconductor structure may be bondedwith the second semiconductor structure by bonding the metal bondingsurface with the dielectric bonding surface at a temperature lower thanroom temperature, e.g., a temperature above 0° C. and belowapproximately 15° C.

In some embodiments, the first semiconductor structure may be bondedwith the second semiconductor structure by bonding the metal bondingsurface with the dielectric bonding surface at a temperature higher thanroom temperature, e.g., a temperature in an range from approximately 30°C. to approximately 100° C.

FIG. 14 illustrates another schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure. Referring to FIG. 14, the first semiconductorstructure is bonded with the second semiconductor structure by bondingthe metal bonding surface with the dielectric bonding surface. In someembodiments, referring to FIG. 14, the first semiconductor structure maybe oriented upside down, such that the metal bonding surface is orienteddownward. Further, the dielectric bonding surface is oriented upward.Accordingly, the dielectric bonding surface and the metal bondingsurface face toward each other and bonded together.

A bonding interface 31 is form between the first semiconductor structureand the second semiconductor structure. The bonding interface 31 is at aplane at which the metal bonding surface is in contact with thedielectric bonding surface.

In some embodiments, the first semiconductor structure may be orientedsuch that the metal bonding surface faces toward left, and the secondsemiconductor structure may be oriented such that the dielectric bondingsurface faces toward right. Accordingly, the metal bonding surface andthe dielectric bonding surface face toward each other and are bondedwith each other.

In some embodiments, the first semiconductor structure may be orientedsuch that the metal bonding surface faces toward right, and the secondsemiconductor structure may be oriented such that the dielectric bondingsurface face toward left. Accordingly, the metal bonding surface and thedielectric bonding surface face toward each other and are bonded witheach other.

The first semiconductor structure may be bonded with the secondsemiconductor structure having the metal bonding surface and thedielectric bonding surface facing various direction, as long as themetal bonding surface and the dielectric bonding surface face towardeach other and are bonded with each other.

In some embodiments, referring to FIG. 1, a heat treatment is applied onthe first semiconductor structure and the second semiconductor structure(S680). During the heat treatment, the first semiconductor structure andthe second semiconductor structure may be annealed at an annealingtemperature. The annealing temperature may be, for example, in a rangefrom approximately 100° C. to approximately 450° C. For example,temperatures of the first semiconductor structure and the secondsemiconductor structure may be increased from an original temperature tothe annealing temperature, kept at the annealing temperature for apreset time period, and further reduced to the original temperature. Theoriginal temperature may be, for example, room temperature. The presettime period may be, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours,etc. The preset time period may be any suitable time period chosenaccording to various application scenarios.

FIG. 15 illustrates a transmission electron microscopy image of anexemplary structure of metal-dielectric bonding consistent with variousdisclosed embodiments of the present disclosure.

In transmission electron microscopy (TEM), an electron beam is directedtoward a sample for imaging. The electron beam passes through thesample, during which electrons interact with the sample. Theinteractions depend on properties of local areas of the sample.Different local areas having different properties lead to differentinteractions with electrons, and thus lead to differences in differentareas of a corresponding TEM image.

Referring to FIG. 15, the structure of metal-dielectric bonding includesa first semiconductor structure 100 a, a second semiconductor structure200 a, and a bonding interface 31 a formed between a first semiconductorstructure 100 a and a second semiconductor structure 200 a. The firstsemiconductor structure 100 a includes a first semiconductor layer 11 a,a first dielectric layer 12 a on the first semiconductor layer 11 a, anda first metal layer 13 a on the first dielectric layer 12 a. The firstmetal layer 13 a includes a metal bonding surface, and the metal bondingsurface faces away from the first semiconductor layer 11 a. The secondsemiconductor structure 200 a includes a second semiconductor layer 21 aand a second dielectric layer 22 a on the second semiconductor layer 21a. The second dielectric layer 22 a includes a dielectric bondingsurface, and the dielectric bonding surface faces away from the secondsemiconductor layer 21 a.

Referring to FIG. 15, the second semiconductor structure 200 a isoriented such that the dielectric bonding surface faces downward, andthe first semiconductor structure 100 a is oriented such that the metalbonding surface faces upward, and the dielectric bonding surface and themetal bonding surface face toward each other, and are bonded with eachother. The bonding interface 31 a is at a plane at which the metalbonding surface and the dielectric bonding surface are in contact witheach other.

The present disclosure provides a structure of metal-dielectric bonding,e.g., a metal-dielectric bonding structure corresponding to anymetal-dielectric bonding method according to various embodiments of thepresent disclosure.

FIG. 13 illustrates a schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure. Referring to FIG. 13, the exemplary structureof metal-dielectric bonding includes a first semiconductor structure100, a second semiconductor structure 200, and a bonding interface 31.The second semiconductor structure 200 is on the first semiconductorstructure 100, and is bonded with the first semiconductor structure 100.

The first semiconductor structure 100 includes a first semiconductorlayer 11, a first dielectric layer 12 on the first semiconductor layer11, and a first metal layer 13 on the first dielectric layer 12. Thefirst metal layer 13 includes a metal bonding surface, and the metalbonding surface faces away from the first semiconductor layer 11.

In some embodiments, the first semiconductor layer 11 may be, forexample, a silicon substrate.

In some embodiment, a material of the first dielectric layer 12 mayinclude, for example, silicon oxide, silicon oxycarbide, siliconnitride, silicon carbon nitride, or any combination thereof.

In some embodiments, a material of the first metal layer 13 may be, forexample, tantalum, titanium, copper, or any combination thereof.

The second semiconductor structure 200 includes a second semiconductorlayer 21 and a second dielectric layer 22 on the second semiconductorlayer 21. The second dielectric layer 22 includes a dielectric bondingsurface, and the dielectric bonding surface faces away from the secondsemiconductor layer 21.

In some embodiments, the second semiconductor layer 21 may be, forexample, a silicon substrate.

In some embodiments, a material of the second dielectric layer 22 mayinclude, for example, silicon oxide, silicon oxycarbide, siliconnitride, silicon carbon nitride, or any combination thereof.

Referring to FIG. 13, the second semiconductor structure 200 may beoriented such that the dielectric bonding surface is oriented downward.That is, the direction from the second semiconductor layer 21 to thesecond dielectric layer 22 points downward. The metal bonding surface isoriented upward. That is, the direction from the first semiconductorlayer 11 to the first metal layer 13 points upward. Accordingly, thedielectric bonding surface and the metal bonding surface face towardeach other and bonded together.

A bonding interface 31 is form between the first semiconductor structureand the second semiconductor structure. The bonding interface 31 is at aplane at which the metal bonding surface is in contact with thedielectric bonding surface.

FIG. 14 illustrates another schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure. Referring to FIG. 14, the exemplary structureof metal-dielectric bonding includes a first semiconductor structure100, a second semiconductor structure 200, and a bonding interface 31.The second semiconductor structure 200 is bonded with the firstsemiconductor structure 100.

The first semiconductor structure 100 includes a first semiconductorlayer 11, a first dielectric layer 12 on the first semiconductor layer11, and a first metal layer 13 on the first dielectric layer 12. Thefirst metal layer 13 includes a metal bonding surface, and the metalbonding surface faces away from the first semiconductor layer 11.

In some embodiments, the first semiconductor layer 11 may be, forexample, a silicon substrate.

In some embodiment, a material of the first dielectric layer 12 mayinclude, for example, silicon oxide, silicon oxycarbide, siliconnitride, silicon carbon nitride, or any combination thereof.

In some embodiments, a material of the first metal layer 13 may be, forexample, tantalum, titanium, copper, or any combination thereof.

The second semiconductor structure 200 includes a second semiconductorlayer 21 and a second dielectric layer 22 on the second semiconductorlayer 21. The second dielectric layer 22 includes a dielectric bondingsurface, and the dielectric bonding surface faces away from the secondsemiconductor layer 21.

In some embodiments, the second semiconductor layer 21 may be, forexample, a silicon substrate.

In some embodiments, a material of the second dielectric layer 22 mayinclude, for example, silicon oxide, silicon oxycarbide, siliconnitride, silicon carbon nitride, or any combination thereof.

Referring to FIG. 14, the second semiconductor structure 200 may beoriented such that the dielectric bonding surface is oriented upward.That is, the direction from the second semiconductor layer 21 to thesecond dielectric layer 22 points upward. The metal bonding surface isoriented downward. That is, the direction from the first semiconductorlayer 11 to the first metal layer 13 points downward. Accordingly, thedielectric bonding surface and the metal bonding surface face towardeach other and bonded together.

A bonding interface 31 is form between the first semiconductor structureand the second semiconductor structure. The bonding interface 31 is at aplane at which the metal bonding surface is in contact with thedielectric bonding surface.

The above described orientations of the first semiconductor structureand the second semiconductor structure are merely for illustrativepurposes and are not intended to limit the scope of the presentdisclosure. The first semiconductor structure and the secondsemiconductor structure in the structure of metal-dielectric bonding mayhave various suitable orientations. For example, in the structure ofmetal-dielectric bonding, the first semiconductor structure may beoriented such that the metal bonding surface faces toward left, and thesecond semiconductor structure may be oriented such that the dielectricbonding surface face toward right. Accordingly, the metal bondingsurface and the dielectric bonding surface face toward each other andare bonded with each other. As another example, the first semiconductorstructure may be oriented such that the metal bonding surface facestoward right, and the second semiconductor structure may be orientedsuch that the dielectric bonding surface face toward left. Accordingly,the metal bonding surface and the dielectric bonding surface face towardeach other and are bonded with each other. The first semiconductorstructure and the second semiconductor structure in the structure ofmetal-dielectric bonding may have any suitable orientations, as long asthe metal bonding surface and the dielectric bonding surface face towardeach other and are bonded with each other.

FIG. 16 illustrates another schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure. Referring to FIG. 16, the structure ofmetal-dielectric bonding includes a first semiconductor structure 100, asecond semiconductor structure 200, and a bonding interface 31. Thesecond semiconductor structure 200 is on the first semiconductorstructure 100, and is bonded with the first semiconductor structure 100.

The first semiconductor structure 100 includes a first semiconductorlayer 11, a first dielectric layer 12 on the first semiconductor layer11, and a first metal layer 13 on the first dielectric layer 12. Thefirst metal layer 13 includes a metal bonding surface, and the metalbonding surface faces away from the first semiconductor layer 11. Insome embodiments, a material of the first metal layer 13 may be, forexample, tantalum, titanium, copper, or any combination thereof.

The second semiconductor structure 200 includes a second semiconductorlayer 21 and a second dielectric layer 22 on the second semiconductorlayer 21. The second dielectric layer 22 includes a dielectric bondingsurface, and the dielectric bonding surface faces away from the secondsemiconductor layer 21. In some embodiments, a material of the seconddielectric layer 22 may include, for example, silicon oxide, siliconoxycarbide, silicon nitride, silicon carbon nitride, or any combinationthereof.

The first semiconductor layer 11 may include, for example, a firstsemiconductor device 111. In some embodiments, the first semiconductordevice 111 be, for example, a power device. The power device maygenerate heat. Such heat may transfer toward the second semiconductorstructure 200. The first metal layer 13 may dissipate or redistributeheat generated by the power device, improving operation stability of thepower device and/or the second semiconductor structure 200. Referring toFIG. 16, straight arrows may indicate heat generate by the power device,and heat may be dissipated or redistributed by the first metal layer 13.The first metal layer 13 may dissipate heat to the air by itself ordissipate heat by further connecting to a heat dissipating apparatus(not shown). Accordingly, operation stability of the power device and/orthe second semiconductor structure 200 can be improved.

In some embodiments, the power device may include, for example, a diode,a power metal-oxide semiconductor field effect transistor (MOSFET), aninsulated gate bipolar transistor, a bipolar junction transistor, or anycombination thereof.

In some embodiments, the first semiconductor device 111 may be, forexample, a device that generates an electromagnetic radiation. Theelectromagnetic radiation may be, for example, visible light, infraredlight, radio wave, ultraviolet, or any combination thereof. The firstmetal layer 13 may block the electromagnetic radiation from reaching thesecond semiconductor structure 200, so as to not affect the secondsemiconductor structure 200 and to facilitate stable operations of thesecond semiconductor structure 200. For example, the first semiconductordevice 111 may be a light-emitting device that generates light, and thefirst metal layer 13 may block the light from reaching the secondsemiconductor structure 200.

In some embodiments, the first semiconductor device 111 may be, forexample, a device that is exposed to an electromagnetic radiation. Theelectromagnetic radiation may be, for example, visible light, infraredlight, radio wave, ultraviolet, or any combination thereof. The firstmetal layer 13 may block electromagnetic radiation from reaching thesecond semiconductor structure 200, so as to not affect the secondsemiconductor structure 200 and to facilitate stable operations of thesecond semiconductor structure 200. For example, the first semiconductordevice 111 may be a pixel wafer that contains photosensitive pixels andis exposed to light. The first metal layer 13 may block the light fromreaching the second semiconductor structure 200. For various features ofthe structure of metal-dielectric bonding, references can be made toabove method embodiments and device embodiments.

FIG. 17 illustrates another schematic view of an exemplary structure ofmetal-dielectric bonding consistent with various disclosed embodimentsof the present disclosure. Referring to FIG. 17, the structure ofmetal-dielectric bonding includes a first semiconductor structure 100, asecond semiconductor structure 200, and a bonding interface 31. Thesecond semiconductor structure 200 is on the first semiconductorstructure 100, and is bonded with the first semiconductor structure 100.

The first semiconductor structure 100 includes a first semiconductorlayer 11, a first dielectric layer 12 on the first semiconductor layer11, and a first metal layer 13 on the first dielectric layer 12. Thefirst metal layer 13 includes a metal bonding surface, and the metalbonding surface faces away from the first semiconductor layer 11.

The second semiconductor structure 200 includes a second semiconductorlayer 21 and a second dielectric layer 22 on the second semiconductorlayer 21. The second dielectric layer 22 includes a dielectric bondingsurface, and the dielectric bonding surface faces away from the secondsemiconductor layer 21. The dielectric bonding surface is bonded withthe metal bonding surface.

The first semiconductor layer 11 may include, for example, a firstsemiconductor device 111, and the second semiconductor layer 21 mayinclude, for example, a second semiconductor device 211.

In some embodiments, referring to FIG. 17, the first semiconductordevice 111 may be, for example, a power device that generates heat,where the heat is indicated by straight filled arrows; and the secondsemiconductor device 211 may be another device that generates or isexposed to an electromagnetic radiation, where the electromagneticradiation is indicated by curved arrows. The electromagnetic radiationmay be, for example, visible light, infrared light, radio wave,ultraviolet, or any combination thereof. The first metal layer 13 maydissipate or redistribute heat generated by the power device; and thefirst metal layer 13 may block the electromagnetic radiation fromreaching the first semiconductor device 111, so as to facilitate stableoperations of the second semiconductor structure 200 and/or the firstsemiconductor layer 11 of the first semiconductor structure 100.

For example, the first semiconductor device 111 may be a CMOS devicethat generates heat, and the second semiconductor device 211 may be apixel wafer that contains photosensitive pixels and is exposed tovisible light or infrared light. The first metal layer 13 may dissipateor redistribute heat generated by the CMOS device, and may block thelight from reaching the first semiconductor layer 11.

A metal-dielectric bonding method and a corresponding metal-dielectricbonding structure consistent with present disclosure can haveapplications for a CMOS image sensor (CIS) and/or a memory device.

In some embodiments, the first semiconductor device 111 may be, forexample, a COMS device of a COMS image sensor (CIS), and the secondsemiconductor device 211 may be, for example, a pixel wafer of the CIS.The pixel wafer of the CIS may include a plurality of pixels. Themetal-dielectric bonding structure may further include other componentsto perform operations of a CIS sensor. For example, the metal-dielectricstructure may further include a color filter array to filter light forthe pixel wafer, and connections between the COMS device and the pixelwafer.

In other embodiments, the first semiconductor device 111 may be, forexample, a CIS sensor. The first semiconductor structure 100 thatincludes the CIS sensor may be bonded to the second semiconductorstructure 200. The second semiconductor device 211 may include, forexample, a memory for storing data collected by the CIS sensor or dataused by the CIS image sensor. The memory may be, for example, a DRAM, aNAND flash memory, a NOR flash memory, any combination thereof, or anyother suitable memory.

In some embodiments, the first semiconductor device 111 may include, forexample, a memory for storing data. The memory may be, for example, aDRAM, a NAND flash memory, a NOR flash memory, any combination thereof,or any other suitable memory. The second semiconductor device 211 maybe, for example, a semiconductor device that collects data and storescollected date in the memory, or a semiconductor device that uses datastored in the memory. The second semiconductor device 211 may be, forexample, a sensor or a hardware processor.

Although the principles and implementations of the present disclosureare described by using specific embodiments in the specification, theforegoing descriptions of the embodiments are only intended to helpunderstand the method and core idea of the method of the presentdisclosure. Meanwhile, a person of ordinary skill in the art may makemodifications to the specific implementations and application rangeaccording to the idea of the present disclosure. In conclusion, thecontent of the specification should not be construed as a limitation tothe present disclosure.

What is claimed is:
 1. A metal-dielectric bonding method, comprising:providing a first semiconductor structure including: a firstsemiconductor layer, a first dielectric layer on the first semiconductorlayer, and a first metal layer on the first dielectric layer, the firstmetal layer having a metal bonding surface facing away from the firstsemiconductor layer; planarizing the metal bonding surface; applying aplasma treatment on the metal bonding surface; providing a secondsemiconductor structure including: a second semiconductor layer, and asecond dielectric layer on the second semiconductor layer, the seconddielectric layer having a dielectric bonding surface facing away fromthe second semiconductor layer; planarizing the dielectric bondingsurface; applying a plasma treatment on the dielectric bonding surface;and bonding the first semiconductor structure with the secondsemiconductor structure by bonding the metal bonding surface with thedielectric bonding surface, wherein one of the metal bonding surface andthe dielectric bonding surface entirely covers and is in direct contactwith an other of the metal bonding surface and the dielectric bondingsurface.
 2. The bonding method according to claim 1, before bonding thefirst semiconductor structure with the second semiconductor structure,further comprising: cleaning the metal bonding surface; and cleaning thedielectric bonding surface.
 3. The bonding method according to claim 2,wherein: cleaning the metal bonding surface includes using a hydrophilicchemical substance to clean the metal bonding surface.
 4. The bondingmethod according to claim 3, wherein: the hydrophilic chemical substanceis ammonia solution or a weak acid, and the weak acid includeshydrofluoric acid, benzoic acid, acetic acid, propanoic acid, or acrylicacid.
 5. The bonding method according to claim 1, wherein: applying theplasma treatment on the metal bonding surface includes treating themetal bonding surface using nitrogen plasma, oxygen plasma, argonplasma, or argon-hydrogen plasma.
 6. The bonding method according toclaim 1, wherein bonding the first semiconductor structure with thesecond semiconductor structure includes: forming a bonding interfacebetween the first semiconductor structure and the second semiconductorstructure.
 7. The bonding method according to claim 1, wherein bondingthe first semiconductor structure with the second semiconductorstructure includes: bonding the first semiconductor structure with thesecond semiconductor structure at room temperature ranging fromapproximately 15° C. to approximately 30° C.
 8. The bonding methodaccording to claim 1, wherein bonding the first semiconductor structurewith the second semiconductor structure includes: bonding the firstsemiconductor structure with the second semiconductor structure at atemperature above 0° C. and below approximately 15° C. or a temperaturein an range from approximately 30° C. to approximately 100° C.
 9. Thebonding method according to claim 1, wherein planarizing the metalbonding surface includes: reducing a surface roughness of the metalbonding surface to approximately 0.5 nm or less by a chemical mechanicalplanarization.
 10. The bonding method according to claim 1, wherein: thefirst semiconductor layer includes a power device that generates heat;and the first metal layer is formed to dissipate the heat generated bythe power device.
 11. The bonding method according to claim 10, wherein:the power device is a diode, a power metal-oxide semiconductor fieldeffect transistor, an insulated gate bipolar transistor, a bipolarjunction transistor, or a combination thereof.
 12. The bonding methodaccording to claim 1, wherein: the first semiconductor layer includes adevice that generates an electromagnetic radiation; and the first metallayer blocks the electromagnetic radiation from reaching to the secondsemiconductor structure.
 13. The bonding method according to claim 1,wherein: the first semiconductor layer includes a complementarymetal-oxide-semiconductor device; and the second semiconductor layerincludes a pixel wafer.
 14. The bonding method according to claim 1,wherein: the first semiconductor layer includes a complementarymetal-oxide-semiconductor device image sensor.
 15. The bonding methodaccording to claim 1, wherein: the first semiconductor layer includes adynamic random-access memory, a NAND flash memory, a NOR flash memory,or a combination thereof.
 16. The bonding method according to claim 1,wherein: a material of the first metal layer is tantalum, titanium,copper, or a combination thereof.
 17. The bonding method according toclaim 1, wherein: a material of the first dielectric layer includessilicon oxide, silicon oxycarbide, silicon nitride, silicon carbonnitride, or a combination thereof.
 18. The bonding method according toclaim 1, after bonding the first semiconductor structure with the secondsemiconductor structure, further comprising: annealing the firstsemiconductor structure and the second semiconductor structure at anannealing temperature in a range from approximately 100° C. toapproximately 450° C.
 19. The bonding method according to claim 1,wherein: planarizing the metal bonding surface is performed beforeapplying the plasma treatment on the metal bonding surface; andplanarizing the dielectric bonding surface is performed before applyingthe plasma treatment on the dielectric bonding surface.
 20. The bondingmethod according to claim 1, wherein: the first semiconductor layerincludes a first semiconductor device, the first metal layer is bondedwith the second dielectric layer and is associated with the secondsemiconductor device to block electromagnetic radiation related to thesecond semiconductor device, and the first metal layer is furtherconnected to a heat dissipating apparatus for heat dissipation of thefirst semiconductor device.